With the impending shutdown of BlackBerry World, it is more important than ever to backup your apps. This tutorial explains how to backup your apps using BlackBerry Swiss Army Knife and how to create single app installer files to make reinstallation more convenient (especially for sharing apps with your friends, post-app'ocalypse).
The best tool for getting third-party apps off a BlackBerry device is BBSAK (BlackBerry Swiss Army Knife). The process of backing up your apps is relatively simple. Install BBSAK, connect your BlackBerry device to your computer via USB cable, and press the "Backup Apps" button. That leaves you with a folder full of .cod files (the actual apps) and one .jad file (the installation file), intended to reinstall all of the apps at once.
After performing a backup with BBSAK, you can then take any of the .cod files, and use the "Create-a-Jad" feature of BBHTool (BBHTool) to create a .jad which will install just those .cod files. So, if you want to create a .jad for an app called 'foo', grab all of the .cods for that app and put them in a folder (let's call the folder 'foo'). Then run BBHTool and use Create-a-Jad, adding those .cods in the Create-a-Jad dialogue box, and editing the fields as necessary. Make the output folder your 'foo' folder, and it will create a .jad file there.
The .jad file and the .cod file(s) must be kept in the same folder for the .jad to work.
From that point, you can put the folder on your device, upload it to your home server where you can build your own app world, or zip it and send it to a friend. As long as the .jad and .cod files are in the same folder, when you click the .jad, the app will install.